That's because he's not using the word 'atheist' the way we use it. He's using it to mean someone who 'hates god', or more accurately, 'resents religion, but still basically believes in god'.

When people say, "I used to be an atheist, until I prayed to Jesus and he saved me," they are not talking about lack-of-belief-atheism at all. It's a bullshit way to pretend that they understand non-believers, when they don't.

Two ways I can see to approach this:

1) Ask him what his reasons were for not believing in god during the time he was atheist. He probably won't understand the question, but this can serve as a starting point to drilling into his beliefs.

2) Or, if you want to try out a newer approach I'm going to try the next time I get a chance, try this: "Yeah, I tried that. It just doesn't work for me.  I prayed to Jesus and all that Jazz, and nothing happened. " To which he'll say something along the lines of "You weren't doing it right, you have to open your heart, blah blah blah."

And then, this is the new tactic, you go, "Yeah, man, I know. I tried that and it really didn't work. Seriously. Maybe it worked for you, but not for me. It's too bad, too, cuz I really wanted to get saved, but now I seriously have doubts whether Jesus really is god, or maybe this is just another one of those man-made religions like Islam. You know, I tried Islam, too ,but it didn't work either. I've tried Judaism, Hinduism, Buddhism, (etc., any religions you can think of that you feel comfortable talking about), and none of them worked. Have you ever tried those ones? No? You should try them. Some of them are really ridiculous, right? Like in Islam, you're supposed to pray five times a day. Ha! That's crazy right? Yeah, I know, Islam is a crazy, dangerous religion, and in any case, I already tried it and it didn't work. So, I tried Christianity, and it didn't work either. Besides, you have to admit, there are some pretty crazy things in Christianity too, right? You know what I mean, like the anti-gay bigotry? What they hell is that all about? Or the cracker turning into Jesus. That's pretty funny, right? Yeah, man, sorry, I'm not interested in that stuff anymore. I gave it up a while ago. I tried em all, and none of them work."

And if he presses the issue, this is the final kicker: "Well, you say it works for you, and I already know it doesn't work for me. And any true religion should work for everybody, right? So since it didn't work for me, I can't believe in it. At the end of the day, if Christianity is true, it should work for anyone who seriously tries it. Right? And I seriously tried it, and it didn't work. So, sorry. Thanks, man, I'm just not interested in that stuff. Tried it. Didn't work."

He may have been someone who rejected social norms because of the hypocrisy or ideal of rebelling.When I run into this argument what seems to be most likely is that they never left theism, but define atheism as a theist would, not as an atheist would and merely define it as " a rejection of God"

There is a difference between rejecting a god on emotional reasons, and rejecting a god on evidence reasons.

I CAN reject a God purely on emotional reasons. And I would be justified on that alone, but by itself is not the core or best reason to reject a god claim.

So when this idiot claims I hate God, I would, IF IF IF IF IF IF IF IF IF IF IF we are assuming existence for argument sake only by default.

What I hate in reality, is that there are fans of such fictional beings who go around claiming these beings are real insisting they are real and have domain over my existence.

But if someone would ask me what I would think of such a being, if proven to be real, with all the disease and crime and war and death, that have never ceased to happen in our species history, I DO HATE GOD, not as a reality, but as a concept.

"God" as a claim has to be the worst invention of humans. It is the biggest clusterfuck superstition that has done nothing to improve the human condition and everything to divide humanity.

So yea. I DO HATE GOD. Just like I would hate the claim that the earth was flat. It may make some feel comfortable but it is a blight on humanity to wallow in such fairy tales.